first
you have set ur utl direcotory.
in 8i, set utl_file_dir in init.ora
in 9i, do this method.
-- login as sys and create the directory.
sys@mutation_mutation > create directory rep_dir as '/home/oracle/scr/ora/rep';

Directory created.

sys@mutation_mutation > grant read on directory rep_dir to mag;

Grant succeeded.

sys@mutation_mutation > grant write on directory rep_dir to mag;

Grant succeeded.

----------------------------------------------------------------------

lets test whether the direcotry works.
now your pl/sql programs can create files in the created direcotry.
your pl/sql programs should make use of builtin UTL_FILE.
-- i have written a very simple utility write_log 
-- that will make use of pl/sql built in utl_file.
-- and will save lotsa code
-- the write_log procedure takes three arguments
--    name of file to be created,message and mode
mag@mutation_mutation > @write_log

Procedure created.

mag@mutation_mutation > begin
  2  write_log('test_utl.txt','this is just samople text.','A');
  3  end;
  4  /

PL/SQL procedure successfully completed.

mag@mutation_mutation > !cat rep/test_utl.txt
this is just samople text.

----------------------------------------------------------------------

now lets create the trigger.
-- this trigger fires for evey inserted row
-- and writes the contents into a OS file.
-- I am passing the name of the file as input
-- note that, i am opening the file script.csv in
-- append mode. so that every time, the records/lines
-- are appended.
-- You have decide an logic to clean the files daily 
-- or whenever required.
-- you can just 'touch' them
mag@mutation_mutation > get tr
  1  create or replace trigger csv_dept
  2  after insert on  dept
  3  for each row
  4  begin
  5  write_log('script.csv','insert into sometable ('''||:new.deptno||''','''||:new.loc||''','''||:new.dname||''','''||sysdate||''');','A');
  6* END;
mag@mutation_mutation > @tr

Trigger created.

mag@mutation_mutation > insert into dept values ('23','mydept','mystreet');

1 row created.

mag@mutation_mutation > /

1 row created.

mag@mutation_mutation > insert into dept values  ('25','asdf','asdf');

1 row created.

mag@mutation_mutation > !pwd
/home/oracle/scr/ora

mag@mutation_mutation > !cat rep/script.csv
insert into sometable ('23','mystreet','mydept','09/19/03');
insert into sometable ('23','mystreet','mydept','09/19/03');
insert into sometable ('25','asdf','asdf','09/19/03');

----------------------------------------------------------------------

-- this is source code for write_log
-- you have to only one change
-- in line 18
-- 18  log_file := UTL_FILE.FOPEN('REP_DIR',fname,mo);
-- i have used this REP_DIR for our example.
-- replace with your directory name created in step1.
-- you can have mutltiple directories say REP_DIR2.
-- create a new packge WRITE_LOG2 and use it.
-- You can give any filename you want, to be crated.

mag@mutation_mutation > get write_log
  1  -- Enterprise Services: Mahesh Rajendran
  2  -- notes:
  3  -- 1.      Stored Procedure to write the log files for the Lawson_etl process
  4  -- 2.      Takees 3 input parameters -> filename, message to be written and Mode (read or write)
  5  -- in which the log file is opened.
  6  -- Output -> written to OS file.
  7  -- 3.      init parameter utl_file_dir = /rman/logs and file permsisions are given.
  8  -- 4.      The Most common exceptions are handled, will add any more.
  9  CREATE OR REPLACE PROCEDURE write_log
 10  (
 11     fname   IN VARCHAR2 ,
 12     message IN VARCHAR2 ,
 13     mo      IN VARCHAR2
 14  )
 15  IS
 16  log_file  UTL_FILE.FILE_TYPE;         -- file handle for the log file
 17  BEGIN
 18  log_file := UTL_FILE.FOPEN('REP_DIR',fname,mo);
 19  UTL_FILE.PUTF(log_file,'%sn',message);
 20  UTL_FILE.FCLOSE(log_file);
 21  EXCEPTION
 22          WHEN NO_DATA_FOUND THEN
 23             DBMS_OUTPUT.PUT_LINE('no_data_found');
 24     WHEN UTL_FILE.INVALID_PATH THEN
 25             DBMS_OUTPUT.PUT_LINE('UTL_FILE.INVALID_PATH');
 26     WHEN UTL_FILE.WRITE_ERROR THEN
 27                  DBMS_OUTPUT.PUT_LINE('UTL_FILE.WRITE_ERROR');
 28             WHEN OTHERS THEN
 29                  DBMS_OUTPUT.PUT_LINE('other stuff');
 30* END;

mag@mutation_mutation >